cross-passage

plural cross-passages

1. An underground passage between two parallel tunnels, provided for use in the event of an emergency.

   At the lowest point, a short length of tunnel was driven alongside the up line, with a cross passage, to serve as a sump and pump house for dealing with any accumulation of water.

   1958 August 29, T. S. Lascelles, “Diamond Jubilee of the Waterloo & City Railway”, in Railway Magazine, page 520

   1 more example

   The smaller cross-passages between the two running tunnels are for use in emergencies. Unlike the main tunnels being excavated by Tunnel Boring Machines (TBMs) Florence and Cecilia, they are dug using remotely controlled mini-excavators.

   2023 December 13, “Network News: HS2 makes good progress on emergency cross-passages... and continues tunnelling from Old Oak Common to Euston”, in RAIL, number 998, page 10

2. An underground passage between two underground station platforms.